The wall — the edge of the Caicos Bank where the seabed drops from less than 20 metres to more than a kilometre — comes closer to the shore at South Caicos than at any other inhabited island in the territory. From January to April humpback whales pass through the Turks Island Passage and divers can sometimes hear them singing underwater. The rest of the year the wall offers reef sharks, turtles, eagle rays, schooling jacks, and a healthy variety of hard coral and giant sponges.
The best-known sites — The Plane, The Arch, Amos's Wall, Shark Hotel — are all within 20 minutes of Cockburn Harbour by boat. A handful of dive operators on the island run trips for guests of the small resorts and for visiting groups from the School for Field Studies. Visibility is regularly 30 metres or better.